how to find or calculate density altitude ...

Is there an instrument or way to calculate density altitude when at the track that doesn't require one of these $$$ weather stations? I like to keep accurate records of my runs including weather conditions and would like to add in DA but don't know how to find or calculate it. I really don't want to spend $500+ on a weather station or predictor although the ones I've seen at the track are very, very nice. It is a FI car so I'll have my laptop with me so if they have wireless there I may be able to pick that up if it helps.

Thanks.

[NewHemi]

If you happen to already have a Porta Tree, you can add a weather station for a couple of hundred bucks...

Or if you are like me, and just wanted a really good reason to buy one, other than just practicing your reaction times, getting one with a weather station sealed the deal.

David
The New Hemi Guy

[mannymen]

Try this site http://www.dragtimes.com/drag-racing...tors-tools.php

[cad]

Yes. You can google the calculations. I believe you'll also need to calculate pressure altitude.
Or -- pickup a Kestrel 4250 for $259 if all you want is DA.

http://cgi.ebay.com/Kestrel-4250--Ra...22161002r14155

[SSDiv6]

If you a an iPod phone, there is an application for it:

http://itunes.apple.com/us/app/densi...313097113?mt=8

or

DA= 145442.16 X [ 1- (17.326 x Pa) / Tr ] 0.235

where:
* DA* = density altitude, feet
* Pa = actual pressure (station pressure), inches Hg
* Tr = temperature, deg R (deg F + 459.67)

[Bob Pagano]

Go to a aircraft surplus and get an Altimeter with a barometer window, less than $100 and dam close. Seen them in tool boxes everywhere, some folks dont know what they are looking at.

[L79racer]

Originally Posted by Bob Pagano

Go to a aircraft surplus and get an Altimeter with a barometer window, less than $100 and dam close. Seen them in tool boxes everywhere, some folks dont know what they are looking at.

Would this work?
http://www.campmor.com/outdoor/gear/Product___89661

[L79racer]

another one.
http://www.campmor.com/outdoor/gear/Product___85329

[Lew Silverman]

Another tool is the Hot Rod Calc which was designed by Calculated Industries and advertised on the NHRA.com homepage. It's a hand-held calculator which has pre-programmed automotive formulas that were designed for drag racers. I've found it useful to calculate basic ET predictions and horsepower estimates. It's now available from Mr. Gasket as Model 8703 for $79.95.

Originally Posted by mannymen

Try this site http://www.dragtimes.com/drag-racing...tors-tools.php

This will work! Exactly what I was looking for especially since it's free. I can check it at the track with my laptop if I have wireless and if not just do it when I go home since there are multiple times to choose from.

That $259 deal also looks good down the road.

Thanks for the great information guys. Really appreciate it.